The rapid expansion of cloud computing and artificial intelligence has driven the demand for faster optical components in data centres to unprecedented levels. A key advancement in this field is the integration of multiple photonic components onto a single chip, enhancing the performance of optical transceivers. Here silicon photonics, benefiting from mature fabrication processes, has gained prominence in both academic research and industrial applications. The platform combines modulators, switches, photodetectors and low-loss waveguides on a single chip. However, emerging telecommunication standards require modulation speeds that exceed the capabilities of silicon-based modulators. To address these limitations, thin-film lithium niobate has been proposed as an alternative to silicon photonics, offering a low voltage–length product and exceptional high-speed modulation properties. More recently, the first demonstrations of thin-film lithium tantalate circuits have emerged, potentially addressing some of the disadvantages of lithium niobate, enabling a reduced bias drift and enhanced resistance to optical damage. As such, this material arises as a promising candidate for next-generation photonic platforms. However, a persistent drawback of such platforms is the lithium contamination, which complicates integration with CMOS fabrication processes. Here we present for the first time the integration of lithium tantalate onto a silicon photonics chip. This integration is achieved without modifying the standard silicon photonics process design kit. Our device achieves low half-wave voltage (3.5 V), low insertion loss (2.9 dB) and high-speed operation (>70 GHz), paving the way for next-generation applications. By minimizing lithium tantalate material use, our approach reduces costs while leveraging existing silicon photonics technology advancements, in particular supporting ultra-fast monolithic germanium photodetectors and established process design kits. Lithium tantalate is heterogeneously integrated with silicon photonic integrated circuits via a micro-transfer printing process in a manner fully compatible with existing workflows. A Mach–Zehnder modulator with an insertion loss of 2.9 dB and 70 GHz operation is demonstrated.
We explore the use of a mobile furniture swarm that are intended to assist users with limited mobility in their daily indoor activities. We focus on the multi-robot coordination problem when a dense target pose configuration is required, such as in an apartment setting. In those cases, the convergence of one robot to the target can be significantly affected by neighboring robots with specific shapes. In this letter, we propose a solution, named Velocity Potential Field Modulation (VPFM), to deal with the dense coordination problem of a polytopic swarm in a decentralized manner. We adapt our method to assistive applications, such as room reconfigurations and facilitating indoor movement of wheelchair users. We evaluate the performance of our method in simulations and on real-world mobile furniture hardware, demonstrating its effectiveness and real-time performance.
This study investigates the impact of seed layer materials on ferroelectric La-doped (Hf, Zr)O2 (La:HZO) capacitor, designed with back-end-of-line (BEOL) compatibility. The seed layers influence the number and size distribution of HZO nano-crystallites in the as-grown state due to differences in surface passivation and oxidation potential, ultimately leading to variations in the final grain size after post-metallization annealing (PMA). An inverse relationship is observed between the initial number of nano-crystallites and the final grain size, attributed to impingement between growing grains during annealing. These distinct grain growth behaviors drive different phase evolutions in the HZO films, depending on pathways in the phase diagram. While WO3 and ZrO2 seed layers result in undesirable grain size distributions and pathways in the phase diagram leading to inferior electrical performances, the TiO2 seed layer yields intermediate nano-crystallite numbers and sizes, promoting sufficient ferroelectric orthorhombic phase formation. These findings indicate that precise control of HZO nanocrystallite formation through seed layer engineering with careful consideration of phase evolution mechanisms, is essential for continued scaling of HZO film thickness in advanced ferroelectric devices.
In this work, different Y-function methodologies for the extraction of the electrical MOSFET parameters permitting to model the current-voltage (I-V) transfer characteristics from weak to strong inversion in ohmic mode of operation are compared on ideal I-V characteristics analytically constructed. It is evidenced that even if important discrepancies between the values of the estimated parameters using these methodologies exist, the access resistances value may be predicted with good accuracy. It is demonstrated that if the inversion charge is calculated by combining its asymptotic laws in weak and in strong inversion, this approximation will lead to an about 20% model-induced error in the moderate inversion range. It is proved that the Y-function strategy which permits the best agreement between the extracted parameter values and the reference ones may be a solution to foresee with lower error the inversion charge behavior from weak to strong inversion even without performing capacitance-voltage measurements.
This study presents a radar-based algorithm for non-invasive heart rate monitoring in intensive care units (ICUs) using a 140 GHz Frequency-Modulated Continuous Wave (FMCW) radar, placed unobtrusively beneath hospital beds. Data were collected from 15 post-operative cardiac patients at Maastricht University Hospital, with an ECG device serving as the ground truth for validation. The proposed algorithm includes data preprocessing, channel selection, heart rate estimation, and post-processing, employing autocorrelation to detect rhythmic patterns and quality metrics to ensure reliable channel selection. The system achieved a mean absolute error (MAE) of 2.22 beats per minute (bpm) with 66% overall coverage, increasing to 98% during sinus rhythm periods. This approach demonstrates robust performance in challenging ICU environments by mitigating noise and motion artifacts and optimizing computational efficiency. These findings highlight the potential of radar-based systems to enhance patient care through continuous, non-invasive vital sign monitoring and validate the algorithm's effectiveness in real-world clinical scenarios.
